i=0
while i!=-1:
    i=int(input('输入分数'))
    if i >= 60:
        if i >= 90:
            print('优秀')
        elif i >= 80 and i < 90:
            print('良好')
        elif i >= 70 and i < 80:
            print('中等')
        else:
            print('及格')
    elif i==-1:
        break
    else:
        print('不及格')

